1. Field of the Invention
The present invention relates to a light source device, an optical scanning device, and an image forming apparatus, and more particularly, to a light source device that emits a laser beam, an optical scanning device that scans a scanning surface to be scanned, and an image forming apparatus that forms an image on a recording medium.
2. Description of the Related Art
One of known image forming apparatuses forming an image using a laser beam scans the surface of a rotating photosensitive drum with a laser beam to form a latent image thereon, develops the latent image with toner to obtain a toner image, and fixes the toner image onto a recording medium such as a paper sheet. Recently, this kind of image forming apparatus is widely used for simplified printing in an on-demand printing system, and there are increasing demands for higher density of an image and faster image output.
In response to such demands, Japanese Patent Application Laid-open No. 2003-211728, for example, suggests an image forming apparatus including a light source with a plurality of light emitting areas arranged monolithically in a two dimensional array, such as a vertical cavity surface emitting laser (VCSEL) array, and being able to scan a plurality of scanning lines on a scanning surface simultaneously using a plurality of laser beams emitted therefrom.
In such a light source having a VCSEL array, light emitting elements are mounted in a ceramic package having a lead frame, and is usually mounted on a substrate for use. The alignment of such a light source package with respect to optical systems is performed, for example, with reference to one of side surfaces of the ceramic package, as disclosed in Japanese Patent Application Laid-open No. 2004-6592.
According to the method disclosed in the Japanese Patent Application Laid-open No. 2004-6592, the ceramic package is pressed against a reference surface, using the elastic force generated by bending the substrate, to align the light source with respect to the optical systems. However, if the substrate is bent, solders on the substrate are likely to peel off, thus degrading reliability of the light source device. Furthermore, because the elastic force generated from the bent substrate greatly weakens over time, it is difficult to maintain the alignment of the light source and the optical system constant for a long time period.